ИСТИНА

Electroplating and electroless chemical deposition are used for formation of catalytically active Re–Ni coatings. Re–Ni deposits prepared by electrodeposition contain 55–88 at. % of rhenium. It is found that these coatings have an amorphous structure and contain metallic nickel and both metallic and oxides forms of rhenium. The oxidized forms of rhenium are obviously oxides containing rhenium in the intermediate oxidation states. Re–Ni cathodes demonstrate high catalytic activity in 1.0 M sodium hydroxide solution. The logarithm of exchange current density of the hydrogen evolution reaction (HER) for the most catalytically active Re–Ni alloys containing 80 at.% of rhenium is –3.4. The obtained materials are stable in alkali solutions under electrolysis conditions, but they are unstable in acidic media. On the contrary, Ni–Re–P coatings obtained by electroless deposition using sodium hypophosphite as a reducing agent are promising candidates for HER electrocatalysis in acidic solutions. The deposits are also X-ray amorphous and contain metallic rhenium, metallic and oxidized forms of nickel, and some phosphorus. Therefore, Re–Ni coatings prepared by electrodeposition are promising for electrocatalysis of HER in alkaline solutions, whereas Ni–Re–P deposits obtained by electroless deposition are attractive candidates for hydrogen evolution in acidic solutions.